Conserving energy in response to environmental and national security challenges is a good idea.

Having the government help consumers invest in energy-efficient appliances as a way to boost demand during a recession also makes sense.

But neither one will work if there is no way of knowing whether the appliances really do conserve energy, and an audit of the federal EnergyStar program raises some serious doubts about how reliable these ratings really are.

The Government Accountability Office reported last month that it has been able to get “Energy Star” approval for some made-up products that are absurdly inefficient. One product was a gasoline-powered alarm clock the size of a generator. Another was an “air purifier” that appeared to be an electric space heater with a feather duster taped to it.

Maria Vargas, an official with the Environmental Protection Agency, which runs the program with the Energy Department, said that the approvals did not pose a problem because the products don’t actually exist. But that misses the point.

If these absurd products received approval, how many real products that are less absurd but just as bad an investment made it through with an EnergyStar seal of approval? Maine Sen. Susan Collins, who asked for the GAO study, rightly points out that the products may not be real but the problem is not made up.

“The program is extraordinarily easy to defraud,” Collins said in a recent interview. As a result, Americans are “ripped off twice,” Collins says, once if they buy an inefficient product and again when they pay their taxes.

The problem which the audit exposes is that the government relies on the applicants to provide accurate information and makes its decisions on that basis.

The Energy Department has promised to set up a system of independent verification for all products, but that should have been done before the tax breaks were handed out.

Clearly, it’s time to pull the brakes on this program before any more money is wasted. Until the EnergyStar label means something, it should not be used as a benchmark for tax breaks. And it won’t mean anything until the government takes the time to weed out the gas-powered alarm clocks.